batman

Sources/Engine/Pieces/Pawn.swift

@@ -0,0 +1,53 @@
+package class Pawn: Piece {
+	package var kind: Kind = .Pawn
+	package weak var board: Board?
+	package var color: Color
+	package var position: Square.Position
+	package var pseudoLegalPositions: [Square.Position] {
+		return []
+	}
+	package var legalPositions: [Square.Position] {
+		return pseudoLegalPositions.filter { isLegal(pos: $0) }
+	}
+
+	package var unicodeRepresentation: String {
+		return color == .Black ? "♟" : "♙"
+	}
+
+	package func move(dst: Square.Position) -> Bool {
+		guard board != nil else {
+			return false
+		}
+
+		if !(legalPositions.contains { $0 == dst }) {
+			return false
+		}
+
+		if let board = board, var s = board[position], var d = board[dst] {
+			s.piece = self
+			d.piece = nil
+		}
+
+		position = dst
+
+		return true
+	}
+
+	package func isLegal(pos: Square.Position) -> Bool {
+		// TODO: Handle "En-Passant"
+		if let board = board, let s = board[pos] {
+			if let p = s.piece {
+				if p.color == color { return false }
+			}
+
+		}
+		return true
+	}
+
+	package init(
+		color: Color, on position: Square.Position
+	) {
+		self.color = color
+		self.position = position
+	}
+}

Sources/Engine/Pieces/Piece.swift

@@ -0,0 +1,48 @@
+public enum Kind: String, CaseIterable {
+	case Pawn, Knight, Bishop, Rook, Queen, King
+
+	public var value: Int8 {
+		switch self {
+		case .Pawn: 1
+		case .Bishop: 3
+		case .Knight: 3
+		case .Rook: 5
+		case .Queen: 9
+		case .King: -1
+		}
+	}
+
+
+	public static subscript(_ c: Character) -> (Self, Color)? {
+		let v = c.uppercased()
+
+		guard v == "N" || (Self.allCases.contains { String($0.rawValue.first!) == v}) else {
+			return nil
+		}
+
+		let kind: Self = switch v {
+			case "P": .Pawn
+			case "N": .Knight
+			case "B": .Bishop
+			case "R": .Rook
+			case "Q": .Queen
+			case "K": .King
+			default: .Pawn
+		}
+
+		let color: Color = c.isUppercase ? .White : .Black
+
+		return (kind, color)
+	}
+}
+
+public protocol Piece {
+	var color: Color { get }
+	var unicodeRepresentation: String { get }
+	var kind: Kind { get }
+	var position: Square.Position { get }
+	var pseudoLegalPositions: [Square.Position] { get }
+	var legalPositions: [Square.Position] { get }
+	func move(dst: Square.Position) -> Bool
+	func isLegal(pos: Square.Position) -> Bool
+}